In an ink jet recording system, methods are available in which various inks such as an aqueous ink, an oil ink, a solvent ink, or a UV curable ink is used.
In recent years, an actinic radiation curable ink jet recording system has received specific attention as a method in which images are formed on a substrate which exhibits low ink absorbability. The aforesaid ink jet recording system includes a solvent type in which reactive monomers are diluted by adding water, aqueous solvents, or various organic solvents, and a solvent-free type in which no solvents remain after curing. In recent years, the solvent-free type ink has received wide attention considering the background in which zero VOC has been demanded.
Known as actinic radiation curable inks which are cured by exposure to actinic radiation such as ultraviolet radiation or electron beams are radically polymerizable inks comprised of acrylate monomers as a main component and cationically polymerizable ink comprised of epoxy monomers or oxetane monomers as a main component.
Many printers are now commercially available which employ aqueous ink, oil ink or solvent ink. By employing these inks, embodiments are known which display sufficient durability.
With regard to ink jet printers employing aqueous ink, various types of suitable members are reported in many publications. For example, Patent Document 1 describes hydrogenated nitrilobutadiene rubber as a blade member, while Patent Document 2 describes ether based polyurethane rubber. Further, in Patent Document 3, a water repellent member is employed as a capping member while in Patent Document 4, employed as a piping member is polypropylene which is produced employing an inventive method.
However, acrylate monomers, epoxy monomers or oxetane monomers, which are employed in actinic radiation curable ink, exhibit properties which are markedly different from dilution solvents employed in conventional aqueous ink, oil ink and solvent ink. As a result, with regard to cleaning of ink jet heads, liquid transfer, and ink storage, and especially durability over an extended period of time, many problems have surfaced. Monomers exhibit properties similar to plasticizers employed as a plastic additive and are easily compatible with many plastics. Consequently, when conventionally employed members are used which come into contact with these inks, it is impossible to exhibit the desired functions due to modification by the actinic radiation curable ink.
These monomers tend to markedly dissolve and swell composition members employed in the liquid transfer system, compared to conventional dilution solvents. As a result, problems have occurred such as degradation of capping properties, degradation of cleaning properties, degradation of liquid transfer properties, and ink tank deformation.
Further, it was discovered that depending on the type of dissolving-out components, problems occurred in which ink jet nozzles were clogged and the rate of curing caused by actinic radiation decreased.
Particularly, even though cationically polymerizable ink comprised of epoxy monomers, oxetane monomers, or vinyl ether monomers exhibits advantages with regard to unpleasant odor, speed, and adhesion onto the substrate, problems have occurred in which dimensions and hardness of members vary due to marked corrosion and swelling of various plastic members.
(Patent Document 1) Specification of Japanese Patent No. 2741788
(Patent Document 2) Specification of Japanese Patent No. 2834949
(Patent Document 3) Specification of Japanese Patent No. 2688258
(Patent Document 4) Specification of Japanese Patent Publication No. 6-39466